Compared to the Old or New Testament, resources for the Septuagint are scant. That being said, there are a number of texts and translations readily available, and more in progress. The standard Greek edition of the Septuagint in Greek was just revised.

Septuaginta (Alfred Rahlfs, ed.; Editio altera/Revised and corrected edition by Robert Hanhart; German Bible Society, 2006). This is the popular edition of the Septuagint -- and the only affordable version with the complete Greek text. Note that this is not a critical text (e.g., there is only a brief critical apparatus). Rahlfs based his text primarily on codex Vaticanus (B), but when necessary (and in his own opinion based on established text-critical principles) he adopts readings found in codex Alexandrinus (A) and codex Sinaiticus (S) so as to represent as closely as possible the "Old Greek" version of the text (i.e., the "original" text). This new “Rahlfs-Hanhart” edition is a minor, yet significant, revision of Rahlfs’ LXX by Robert Hanhart. This revision is a stop gap measure, since a new critical edition of the LXX Psalms is many years off and there were many small errors in the original edition that needed to be corrected. In addition to correcting small errors, Hanhart also made some modifications to the critical apparatus, including redescribing the way appeals to textual traditions were quantified as well as the inclusion of a number of other uncials and recensions where the first edition only mentioned B, S, or A. Buy from Amazon.ca | Buy from Amazon.com

Considering that the new revision does not change the substance of Rahlfs's text, you may save a bit of money by purchasing the first edition:

Critical Editions of the LXX

Advanced students will want to acquaint themselves with the critical editions of the Septuagint. For a statement on critical editions by the International Organization of Septuagint and Cognate Studies, see here.

This is the major critical edition of the LXX published by Vandenhoeck & Ruprecht, often referred to as the "Göttingen Septuagint" series. This multi-volume collection is still in production with over twenty volumes published to date:

The Old Testament in Greek according to the Text of Codex Vaticanus

In contrast to the eclectic text of the Göttingen series, this older critical edition, known as the "Larger Cambridge Septuagint," is a diplomatic text, reproducing Codex Vaticanus with a critical apparatus with variant readings from other manuscripts. Edited by Alan E. Brooke, Norman McLean, and Henry St John Thackeray, this series is incomplete, with only Genesis through Esther from the Protestant OT as well as 1 Esdras, Judith, and Tobit from the Apocrypha ever published:

Alan E. Brooke and Norman McLean. Genesis. The Old Testament in Greek according to the Text of Codex Vaticanus, 1,1. Cambridge University Press, 1906.

Alan E. Brooke and Norman McLean. Exodus and Leviticus. The Old Testament in Greek according to the Text of Codex Vaticanus, 1,2. Cambridge University Press, 1909.

Alan E. Brooke and Norman McLean. Numbers and Deuteronomy. The Old Testament in Greek according to the Text of Codex Vaticanus, 1,3. Cambridge University Press, 1911.

Alan E. Brooke and Norman McLean. Joshua, Judges, Ruth. The Old Testament in Greek according to the Text of Codex Vaticanus, 1,4. Cambridge University Press, 1917.

Alan E. Brooke, Norman McLean, and Henry St. John Thackeray. 1-2 Samuel. The Old Testament in Greek according to the Text of Codex Vaticanus, 2,1. Cambridge University Press, 1927.

Alan E. Brooke, Norman McLean, and Henry St. John Thackeray. 1-2 Kings. The Old Testament in Greek according to the Text of Codex Vaticanus, 2,2. Cambridge University Press, 1930.

Alan E. Brooke, Norman McLean, and Henry St. John Thackeray. 1-2 Chronicles. The Old Testament in Greek according to the Text of Codex Vaticanus, 2,3. Cambridge University Press, 1932.

Alan E. Brooke, Norman McLean, and Henry St. John Thackeray. Esdras, Ezra-Nehemiah. The Old Testament in Greek according to the Text of Codex Vaticanus, 2,4. Cambridge University Press, 1935.

Alan E. Brooke, Norman McLean, and Henry St. John Thackeray. Esther, Judith, Tobit. The Old Testament in Greek according to the Text of Codex Vaticanus, 3,1. Cambridge University Press, 1940.

These critical editions of the LXX are quite expensive and difficult to obtain. If interested, they may be available through booksellers specializing in biblical studies like Eisenbrauns (www.eisenbrauns.com) or Dove Books (www.dovebook.com). In addition, Amazon.ca (for fellow Canadians) or Amazon.com may have them available new or used.